Islahb



L. G. HOWARD.

SPARK PLUG.

.APPLICATION FILED JUNEIS, 1920.

1 ,41 5,4147. Patented May 9, 1922.

Fiel.

LORENZO HC1/YARD, F PR SPARK LellC/iw.

` Application nled June l5,

T 0 @ZZ fro/tom tj/wy concern Be it known that 1, -Lonnnzo G. HOWARD, a citizen ofthe United States, residing at Providence, in the county of Providence and State of Rhode Island, have invented certain new and useful Improvements in a Spark Plug, of which the following is a speciication.

My' invention relates to a spark plug.

Among ,they important objects may be mene tioned, the` provision of kan karticle of this type which can hardly fail to lire eitherl in oil or grease; will produce ive or any plurality of sparks ypracticallysimultaneously; onel having electrodes preterablyl shapedso as to retain the porcelain should thesaine break so that it cannot become dislocated or all into a position where it can score the cylinder of the engine; one having a visible gap means whereby the condition or action of the plug may be readilyy observed; one yin which said means will bein the nature of an inten- 1 siier and have its parts covered'and protected from the entrance of material which might short-circuit it and one of the generally improved, vsimplified and more efficient construction hereinafter described and illustrated in accompanying drawings of one preferred embodiment, wherein:

Figure 1 is an elevation of the improved Plug.;

Figure 2 1s an enlarged vertical sectional View of the plug;

Figure 3 is a plan View ot the insulating core; and

Figure 4 is au enlarged bottom view ot the plu lge'lierring specifically to the drawings, 5 designates the core or plug body, which is of insulating material of any'preierred kind, for instance, porcelain. 'Removably and centrally located in the core is an electrode 6 having a head 7, preferably substantially conical as shown and being relatively wide to overlap the bottomy of the core so as to be incapable of movement upwardly thereinto. Electrode 6 may be removed by downward movement. Resting upon the core is a cage or insulating body 8, for instance of porcelain, provided with a transverse slot or win-k dow 9. The cage is also provided with a depression or recess which receives a projection 10 of the core to assist in centering and positioning the core and cage relatively. A central opening is also provided in the cage to removably receive the electrode 6. Dis- Specification of 'Letters Patent.

6 at the head 7.

ATENT orric ovrnnnon, n-nonn isn/inn.

rinus.`

Patented May 9, 1922.

i920. serien no. seais/i,

posed inthe window 9 is a nut 11 which engages screw threads on electrode 6 to se- Also removably mounted in the cage 8 in o alignment with electrode 6 and in relatively close relation therewith as shown is an electrode section 12, fastened in place by a nut 13 disposed in the window and engaging screwthreads on the section 12 and by a nut 14 engaging screw threads on section 12 and resting on top ot the cage. A binding nut 15cooperates with the nut 14 to connect a wire or conductor to the electrode sections12e-G, and it rides on the same screw threads as nut 14.

l lt will'be Vnoticed that a spark gapis provided between the electrode sections 6 and 12 which will serve to intensity the spark. Also this particular means being located in the window of the cage may be observed at all times to ascertain thel working etliciency,thereof.` lt is preferably protected by means which will prevent the entrance of short-circuiting material and it may be in the nature of a mica or other transparent tube 16 into which projections 17 and 18 on the nuts 11 and 13 respectively extend to removably mount it.

y Embedded in the core 5, are a plurality et electrodes 19, preferably hooked at 20 to facilitate anchorage in the core. The core has openings or recesses shaped like the hook ends 20 and thus the electrodes 19 need not be fastened permanently in the core. They cannot become displaced since cage 8 rests on them. At the lower extremities these electrodes 19 are preferably olset and curved as at 21 to provide spark gaps between them and so that onev o1 them at 22 will be in spark gap relation with electrode Also one of the portions 21 is in spark gap relation with an electrode 23 carried in any suitable manner by a bushing or shell 24 to be grounded as usual to the motor casing.

Said bushing or shell 24 may be ot any desired'shape but is preferably provided with screw threads at 25 whereby ,it may be screwedv into the motor casing and with a suitabley wrench-engaging portion 26.

Core 5 preferably has an outwardly eX- tending annular rib or ring 27 integral with it which extends into an enlarged chamber 28 provided within the shell 24 and rests on a ledge 29 therein. A gland 30, provided with a Wrench-engaging head SE1 may extend into the chamber to engage the ring 27 to secure the core to the shell. Vllhe shell and gland are preferably screvv threaded to each other at 32. Gaskets 33 may be provided on opposite sides of the ringy in order to provide a gas-tight joint at this point.

ln use, the gap between the electrode sections o and 12 may be observed When desired to ascertain Whether or not the cylinder to which the glug` applies is firing. The circuit is formed Yfrom the battery or magneto or other source through a conductor connected by the nut 15 to electrode 12 jumpiiig therefrom and becoming intensified at the gap between it and electrode 6, to the electrode 6 to the portions 21 and 22 to electrode 23 to the shell which is grounded as described- A plurality of sparks Will be givein one at each of the gaps between the portions 219 22 and 23 as will be understood.

lt will be noticed that the electrodes 19 at the portions in the core arel straight. This construction permits equal or even contraction and expansion olf the core so as to minimize the chances of cracking. Should it eraclf.. however. these electrodes 19 will serre to retain the Vtragments together so that they cannot tall into lthe cylinder or reach the saine in any Way to injuriously score it.

Since merely the preferred embodiment oi the invention has been illustrated and described7 it is to be understood that changes in the details of construction7 coinhinations and arrangements of the parts may be resorted to Within the spirit and scope oi the invention as defined by appended claim.

I claim:

A spark plug having` a core7 an electrode loosely mounted therein, a cage resting on the core and said electrode, intereng'aging` means intermediate the core and cage, a second electrode. said second electrode being loosely mounted in the core and said cage, a head on the second electrode to underlap the core and to cooperate with the first electrode, the cage having a Window. a nut in said Window engaging the second eleotrode to prevent displacement thereof, a third electrode. said third electrode being mounted by the cage and having1 a fastening nut in said Window, projections on the nuts in said Window, a visual protector for the electrodes in said Window and intoivhieh said projections extend to mount it, a bushing, means to secure the core to the bushing', and electrode means on the bushing to cooperate with the said electrodes.

ln testimony whereof, l have ailixed my signature in the presence oi tivo Witnesses.

LGRENZO G. HOWARD. Vitnesses EDWIN J. TETLOW, GEORGE H. HOWARD. 

